Power-transmission belt requirements

Yes. Flat belts one inch or less in width, flat belts two inches or less in width that are free from metal lacings or fasteners, round belts one-half inch or less in diameter, and single-strand V-belts 13/32 inch or less in width are exempt when operating at 250 feet per minute or less, as listed in 1910.219(a)(1).

• See each specific exemption in 1910.219(a)(1)(i)–(iv) for exact sizes and conditions.

Yes. Vertical and inclined belts not more than two and one-half inches wide, running less than 1,000 feet per minute, and free from metal lacings or fastenings may be guarded with a nip-point belt-and-pulley guard under 1910.219(a)(2).

• Ensure the belt has no metal lacings/fastenings and that the chosen nip-point guard actually prevents contact with the nip area.

You may guard only the sides and face sections of nip-point belt and pulley guards in the textile industry, provided the guard extends at least 6 inches beyond the rim on the in‑running and off‑running sides and at least 2 inches away from the rim and face in all other directions, per 1910.219(a)(3).

• This limited guarding recognizes heavy lint deposits and the associated fire hazard; still follow the exact extension distances specified in the standard.

Guardrails for such flywheels must be placed not less than 15 inches nor more than 20 inches from the rim, as required by 1910.219(b)(1)(ii).

• If a flywheel extends into a pit or is within 12 inches of the floor, a standard toeboard must also be provided.

You may attach a disk to the exposed side of the flywheel to cover spokes and present a smooth surface and edge, provided it allows periodic inspection; any dangerous projections not covered must be cut off or covered, as permitted by 1910.219(b)(1)(iv).

• An open space not exceeding 4 inches between the disk edge and wheel rim is allowed to facilitate turning the wheel.

Guards installed over working areas must be strong enough to hold the weight of the flywheel in the event of a shaft or wheel mounting failure, as required by 1910.219(b)(1)(vi).

• Design guards to resist the static and dynamic loads that would occur if the flywheel detached.

Each continuous line of shafting must be secured in position against excessive endwise movement, per 1910.219(c)(1)(i).

• Use collars, thrust bearings, shoulders, or other positive means to prevent unsafe axial displacement.

All exposed parts of horizontal shafting seven feet or less from the floor or working platform must be protected by a stationary casing enclosing the shafting completely or by a trough enclosing the sides and top (or sides and bottom) as location requires, according to 1910.219(c)(2)(i).

• Exceptions apply only for runways used exclusively for oiling or running adjustments; trough sides should extend at least two inches beyond the shafting.

Projecting shaft ends must present a smooth edge and end and may not project more than one-half the diameter of the shaft unless guarded by nonrotating caps or safety sleeves, per 1910.219(c)(4)(i).

• If caps or sleeves are used, ensure they are nonrotating and securely fitted to eliminate entanglement hazards.

You may omit the usual safeguards in rooms used exclusively for power-transmission equipment only if the area is locked against unauthorized entrance, vertical clearances in passageways are at least 5 feet 6 inches, illumination meets ANSI A11.1-1965 (R-1970) as incorporated by [1910.6], and the oiler's route is protected to prevent accidents, as specified in 1910.219(c)(5)(i)–(iii) and (v).

• These conditions are strict: if any are unmet, full guarding per the section is required.

Pulleys any part of which are seven feet or less from the floor or working platform must be guarded in accordance with the standards specified in paragraphs (m) and (o) of the section, per 1910.219(d)(1).

• Consult the requirements in 1910.219(m) and 1910.219(o) for guard construction and spacing details.

A guide must be provided to prevent the belt from leaving the pulley on the side where insufficient clearance exists unless the distance to the nearest fixed pulley, clutch, or hanger exceeds the width of the belt in use, per 1910.219(d)(2)(i).

• If clearance is limited, install a suitable guide to keep the belt aligned and prevent side run-off.

No. Pulleys with cracks or pieces broken out of rims shall not be used, as stated in 1910.219(d)(3).

• Replace or properly repair damaged pulleys before returning them to service to avoid failure and flying debris hazards.

The guard must extend to at least 15 inches above the belt or to a standard height; if both runs are 42 inches or less from the floor, the belt must be fully enclosed in accordance with paragraphs (m) and (o), per 1910.219(e)(1)(i).

• For low-mounted belts (≤42 inches), full enclosure is mandatory to prevent contact and entanglement.

Overhead horizontal belts more than seven feet above the floor must be guarded for their entire length if any of these conditions apply: they are located over passageways or work places and travel 1,800 feet or more per minute; the center-to-center distance between pulleys is ten feet or more; or the belt is eight inches or more in width, as listed in 1910.219(e)(2)(ii)(a)–(c).

• If none of these conditions apply, localized guarding may be sufficient, but assess risk before deciding.

Either completely bar the passage with a guardrail or other barrier meeting paragraphs (m) and (o), or, if passage is necessary, provide a platform over the lower run guarded on either side by a railing filled in with wire mesh or a solid barrier and guard the upper run to prevent contact, according to 1910.219(e)(2)(iii)(a)–(b).

• In powerplants only, guarding the lower run may be sufficient; otherwise both runs need protection to prevent contact or objects falling into the belt.

All guards for inclined belts must be arranged so that a minimum clearance of seven feet is maintained between the belt and the floor at any point outside the guard, per 1910.219(e)(3)(ii).

• This prevents accidental contact by workers walking under or near the guarded inclined belt.

If the cone is located less than 3 feet from the floor or working platform, the cone pulley and belt must be guarded to a height of 3 feet regardless of whether the belt is endless or laced, as required by 1910.219(e)(5)(iii).

• That guard must adequately prevent access to the nip point and pulley steps.

Suspended counterbalanced tighteners and all parts must be of substantial construction, securely fastened, have securely capped bearings, and include means to prevent the tightener from falling if the belt breaks, per 1910.219(e)(6)(i).

• Where counterweights are exposed and not guarded by location, they must be encased to prevent accidents (1910.219(e)(6)(ii)).

Gears may be guarded by a complete enclosure, by a standard guard at least seven feet high extending six inches above the mesh point, or by a band guard covering the face with flanges extended inward beyond the root of the teeth, as allowed by 1910.219(f)(1)(i)–(iii).

• If any portion of a gear train guarded by a band guard is less than six feet from the floor, a disk guard or complete enclosure to six feet is required.

Yes. All sprocket wheels and chains must be enclosed unless they are more than seven (7) feet above the floor or platform; manually operated sprockets are exempt. See the guarding requirement in 1910.219 which explains the 7-foot exception and the manual-sprocket exclusion.

You must provide openings with hinged or sliding self-closing covers for locations that require frequent oiling, and provide oil feed tubes to points not readily accessible if lubricant will be added while machinery is running. See the openings for oiling requirement in 1910.219(f)(4).

The driving point of any friction drive that is exposed to contact must be guarded; arm or spoke friction drives, web friction drives with holes in the web, and projecting belts on friction drives where exposed to contact must be fully enclosed or otherwise guarded. See the guarding friction drives rule in 1910.219(g).

Projecting keys, setscrews, and other projections on revolving parts must be removed, made flush, or covered by a metal guard, with exceptions for keys or setscrews inside enclosed gear or sprocket casings and for keys/setscrews/oilcups in hubs of pulleys under 20 inches where they lie in the plane of the rim. See 1910.219(h)(1).

Revolving collars must be cylindrical and their screws or bolts must not project beyond the largest periphery; shaft couplings must be built so bolts, nuts, setscrews, or revolving surfaces do not present a hazard, although covered safety sleeves or flush/countersunk hardware parallel with the shaft are permitted. See 1910.219(i)(1) and 1910.219(i)(2).

All drip cups and pans must be securely fastened. This is a direct requirement for proper oiling facilities under 1910.219(j).

Clutches, cutoff couplings, or clutch pulleys with projecting parts located seven (7) feet or less above the floor or working platform must be enclosed by a stationary guard constructed in accordance with the standard; a U-type guard is allowed. See 1910.219(k)(1).

For new installations on or after August 31, 1971, tight and loose pulleys must have a permanent belt shifter with mechanical means to prevent belts from creeping from the loose to the tight pulley; shifter and clutch handles shall be rounded and placed as far as practicable from accidental contact but within easy reach, and if a handle is not directly over a machine or bench it must be cut off at 6 feet 6 inches above floor level. See 1910.219(l)(1)(i) and 1910.219(l)(1)(ii).

No. The use of belt poles as substitutes for mechanical shifters is not recommended by the standard. See 1910.219(l)(2).

Guards should be made of materials like expanded metal, perforated or solid sheet metal, or wire mesh on a frame of angle iron or iron pipe; all metal must be free from burrs and sharp edges, and the chosen metal screens or mesh must be securely fastened to the frame. See 1910.219(m)(1)(i), 1910.219(m)(1)(ii), and 1910.219(m)(2)(i).

Guards for horizontal overhead belts must run the entire length of the belt and follow the line of the pulley to the ceiling or be carried to the nearest wall so the belt is effectively enclosed. See 1910.219(o)(3)(i).

The interior surface of guards that the belt might contact must be smooth and free of projections; overhead belt guards must be at least one-quarter wider than the belt (but need not exceed six inches clearance on each side), and overhead rope or block-and-roller-chain-drive guards must be at least six inches wider than the drive on each side; specific clearances for silent chains are also provided in 1910.219(o)(3)(iii).

Guardrails must be 42 inches in height with a midrail between the top rail and the floor; posts should be not more than eight feet apart and constructed of specified pipe, metal shapes, or wood sizes; toeboards must be at least four inches high and may be wood, metal, or metal grill not exceeding one-inch mesh. See 1910.219(o)(5)(i), 1910.219(o)(5)(ii), and 1910.219(o)(5)(iii).

All power-transmission equipment must be inspected at intervals not exceeding 60 days and kept in good working condition at all times. See the inspection and care requirement in 1910.219(p).

Shafting must be kept in alignment and free from rust and excess oil or grease, and where explosives, explosive dusts, flammable vapors, or flammable liquids exist you must consider the hazard of static sparks from shafting. See 1910.219(p)(2)(i) and 1910.219(p)(2)(ii).

Pulleys must be kept in proper alignment to prevent belts from running off. See the pulley care provision in 1910.219(p)(5)(i).

No. Belts that must be shifted by hand and belts within seven (7) feet of the floor or working platform that are not guarded must never be fastened with metal or with any fastening that by construction or wear will constitute an accident hazard. This requirement appears in the belt fastening and guarding provisions at 1910.219(m).

If lubricant must be added while machinery is in motion, all points not readily accessible must have oil feed tubes so lubricant can be introduced without exposing workers to moving parts. See 1910.219(f)(4).

Temporary re-energization for tasks like testing or positioning is allowed only when necessary and employers must follow a specific sequence of protective steps (clear tools/materials, remove employees from hazard area, remove lockout/tagout devices as specified, perform testing with effective employee protection, then re-isolate and reapply LOTO if further servicing is needed). See OSHA's clarification of the minor servicing exception and temporary re-energization procedures in the LOTO interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2024-10-21 and the requirements of 29 CFR 1910.147 referenced therein.